Stabilizing platform

ABSTRACT

The present invention provides an apparatus and related methods for stabilizing a payload device such an imaging device. The methods and apparatus provide fast response time for posture adjustment of the payload device while reducing the energy used.

CROSS-REFERENCE

This application is a continuation application of U.S. application Ser.No. 14/045,606, filed on Oct. 3, 2013, which is a continuation-in-partapplication of International Application Nos. PCT/CN2011/082462, filedon Nov. 18, 2011, PCT/CN2011/079704, filed on Sep. 15, 2011, andPCT/CN2011/079703, filed on Sep. 15, 2011, which claim priority fromChina Patent Application Nos. 201110268339.6, filed on Sep. 9, 2011, and201110268445.4, filed on Sep. 9, 2011, the content of each of which ishereby incorporated by reference in their entirety.

BACKGROUND OF THE INVENTION

In the fields of videography, photography and/or surveillance, a carrier(e.g., an aircraft, vehicle, ship, robot or a human) is typically usedfor carrying a payload device such as an imaging device (e.g., videocamera, camera) or the like. Such a carrier is typically subject tomovement such as high-frequency vibration and/or low-frequency shake,causing similar movement of the payload device and affecting operationof the payload device. When the payload device is an imaging device, themovement of the carrier may translate to poor-quality images acquired bythe imaging device.

To provide stability to the payload device, a stabilizing platformmounted on the carrier is typically used to carry the payload device.Such stabilization platforms may provide stability to the payload deviceby detecting posture changes in the payload device and reversecompensating the detected posture changes.

Traditionally, such reverse compensation has been provided by mechanicalgear drives. However, such mechanical gear drives typically have adelayed response with a relatively long response time. As such, suchmechanical gear drives can be inadequate for providing quick and dynamicadjustment of payload device postures, for example, to counteract thevarious posture changes of the carrier of the payload device. Inparticular, when the payload device is an imaging device, it may bedifficult to provide high-quality images because of the delay.

SUMMARY OF THE INVENTION

There exists a considerable need for apparatus and method that canprovide stability and rapid response to posture adjustments. The presentinvention addresses this need and provides related advantages as well.

Methods and apparatus for providing stability are provided herein.According to an aspect of the present invention, an apparatus isprovided that comprises a frame assembly adapted to hold a device, acontroller assembly comprising a measurement member configured to obtainstate information with respect to at least a pitch, roll, and yaw axesof the device, the roll axis intersecting with the device, a controllerconfigured to provide one or more motor signals based at least in parton posture information calculated from the state information; and amotor assembly configured to directly drive the frame assembly inresponse to the one or more motor signals so as to allow the device torotate around at least one of the pitch, roll or yaw axes. The devicecan be configured to capture images. The measurement member can includeone or more inertial sensors. The state information can include at leastan angular velocity of the device. The frame assembly can comprise afirst frame member configured to be coupled to the device, a secondframe member rotatably coupled to the first frame member on the pitchaxis of the device, and a third frame member rotatably coupled to thesecond frame member on the roll axis of the device. The motor assemblycan comprise a first motor configured to directly drive the first framemember to rotate around the pitch axis in response to at least one ofthe one or more motor signals; and a second motor configured to directlydrive the second frame member to rotate around the roll axis in responseto at least one of the one or more motor signals.

In some embodiments, the frame assembly can further comprise a fourthframe member, the fourth frame member rotatably coupled to the thirdframe member on a yaw axis of the device; and the motor assembly furthercomprises a third motor configured to directly drive the third framemember to rotate around the yaw axis in response to at least one of theone or more motor signals.

In some embodiments, the center of gravity of (i) the device and (ii)the first frame member, can be located on the pitch axis. The center ofgravity of (i) the device, (ii) the first frame member, and (iii) thesecond frame member, can be located on the roll axis. And the center ofgravity of (i) the device, (ii) the first frame member, (iii) the secondframe member, and (iv) the third frame member, can be located on the yawaxis.

According to another aspect of the present invention, an apparatus isprovided that comprises a frame assembly adapted to hold an imagingdevice, the frame assembly comprising a first frame member configured tobe coupled to the imaging device, a second frame member rotatablycoupled to the first frame member on a pitch axis of the imaging device,and a third frame member rotatably coupled to the second frame member ona roll axis of the imaging device; a controller assembly comprising ameasurement member configured to obtain state information with respectto at least the pitch, roll, and yaw axes of the imaging device and acontroller configured to provide one or more motor signals based atleast in part on posture information calculated from the stateinformation; and a motor assembly configured to directly drive the frameassembly in response to the one or more motor signals so as to allow theimaging device to rotate around at least one of the pitch, roll or yawaxes.

In some embodiments, the roll axis can intersect with the imagingdevice. The motor assembly can comprise a first motor configured todirectly drive the first frame member to rotate around the pitch axis inresponse to at least one of the one or more motor signals; and a secondmotor configured to directly drive the second frame member to rotatearound the roll axis in response to at least one of the one or moremotor signals. The frame assembly can further comprise a fourth framemember, the fourth frame member rotatably coupled to the third framemember on a yaw axis of the imaging device. The motor assembly canfurther comprise a third motor configured to directly drive the thirdframe member to rotate around the yaw axis in response to at least oneof the one or more motor signals.

In some embodiments, a stator of the first motor can be affixed to thefirst frame member and a rotor of the first motor can be affixed to thesecond frame member, or the rotor of the first motor can be affixed tothe first frame member and the stator of the first motor can be affixedto the second frame member. In some embodiments, a stator of the secondmotor can be affixed to the second frame member and a rotor of thesecond motor can be affixed to the third frame member, or the rotor ofthe second motor can be affixed to the second frame member and thestator of the second motor can be affixed to the third frame member.

According to another aspect of the present invention, an apparatus isprovided that comprises a frame assembly adapted to hold a device; acontroller assembly comprising an inertial measurement member configuredto obtain state information comprising at least angular velocity andlinear acceleration of the imaging device and a controller configured toprovide one or more motor signals based at least in part on postureinformation calculated from the state information; and a motor assemblyconfigured to directly drive the frame assembly in response to the oneor more motor signals so as to allow the device to rotate around atleast one of the pitch, roll or yaw axes.

In some embodiments, the frame assembly can comprise a first framemember configured to be coupled to the device; a second frame memberrotatably coupled to the first frame member on a pitch axis of thedevice; and a third frame member rotatably coupled to the second framemember on a roll axis of the device that intersects with the device. Themotor assembly can comprise a first motor configured to directly drivethe first frame member to rotate around the pitch axis in response to atleast one of the one or more motor signals; and a second motorconfigured to directly drive the second frame member to rotate aroundthe roll axis in response to at least one of the one or more motorsignals.

In some embodiments, the frame assembly can further comprise a fourthframe member, the fourth frame member rotatably coupled to the thirdframe member on a yaw axis of the device. The motor assembly can furthercomprise a third motor configured to directly drive the third framemember to rotate around the yaw axis in response to at least one of theone or more motor signals. The frame assembly can further comprise anadjustment member for adjusting at least one of the pitch, roll, or yawaxis relative to the frame assembly.

In some embodiments, a connecting assembly may can be further providedthat connects a distal end of the second frame member and a distal endof the third frame member so as to support and stabilize the secondframe member when the second frame member rotates relative to the thirdframe member. The connecting assembly can comprise a first connectingmember, a second connecting member, and a third connecting member, whichare sequentially and hingedly connected; a free end of the firstconnecting member is hingedly connected with a first distal end of thesecond frame member; a free end of the third connecting member ishingedly connected with a second distal end of the second frame member;and the second connecting member is connected with the third framemember. In some embodiments, the motor assembly can comprise a fourthmotor configured to directly drive the second connecting member torotate relative to the third frame member.

According to another aspect of the present invention, an unmanned aerialvehicle (UAV) is provided that comprises a base coupled to the apparatusdiscussed herein.

According to another aspect of the present invention, a method forcontrolling the apparatus discussed herein is provided. The method cancomprise calculating, by the controller assembly, posture informationbased at least in part on the state information; providing, by thecontroller assembly, one or more motor signals to the motor assemblybased at least in part on the calculated posture information; and inresponse to the one or more motor signals, driving, by the motorassembly, the frame assembly to rotate around at least one of the pitch,roll, or yaw axis.

According to another aspect of the present invention, a method for imageacquisition is provided. The method can comprise remotely operating theunmanned aerial vehicle (UAV) to approach an object, the UAV beingcoupled to the apparatus discussed herein; and controlling the apparatusto stabilize a device held by the frame assembly of the apparatus so asto improve quality of images captured by the device.

INCORPORATION BY REFERENCE

All publications, patents, and patent applications mentioned in thisspecification are herein incorporated by reference to the same extent asif each individual publication, patent, or patent application wasspecifically and individually indicated to be incorporated by reference.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity inthe appended claims. A better understanding of the features andadvantages of the present invention will be obtained by reference to thefollowing detailed description that sets forth illustrative embodiments,in which the principles of the invention are utilized, and theaccompanying drawings of which:

FIG. 1 illustrates a view of an assembled stabilizing platform with apayload device, in accordance with an embodiment of the presentinvention.

FIG. 2 illustrates an exploded view of a stabilizing platform with apayload device, in accordance with an embodiment of the presentinvention.

FIG. 3 illustrates an exploded view of a stabilizing platform with apayload device, in accordance with an embodiment of the presentinvention.

FIG. 4 illustrates an exploded view of a stabilizing platform with apayload device, in accordance with an embodiment of the presentinvention.

FIG. 5 illustrates a view of an assembled stabilizing platform with apayload device, in accordance with an embodiment of the presentinvention.

FIG. 6 illustrates a view of an assembled stabilizing platform with apayload device, in accordance with an embodiment of the presentinvention.

FIG. 7 illustrates a view of an unmanned aerial vehicle carrying astabilizing platform with a payload device, in accordance with anembodiment of the present invention.

FIG. 8 illustrates an exploded view of an exemplary unmanned multi-rotoraircraft carrying a stabilizing platform with a payload device, inaccordance with an embodiment of the present invention. The platformincludes a three-axis stabilizing platform such as the one described inthe exemplary embodiment 2. The exemplary unmanned multi-rotor aircraftof FIG. 8 includes a multi-rotor mount 200 and circuit components. Themulti-rotor mount 200 include a base 21, at least three support arms 22connected to the base 21, rotor members 23 coupled to the distal ends ofthe support arms 22, and multiple support frames 24 used for positioningthat extend outward from the base 21. It is appreciated that the numberof support arms 22 is not limited to three but can be four, six eight orany suitable number. The support arms 22 can be connected to the base 21via a plugging mechanism, welding, screws, riveting, and the like. Thethee-axis stabilizing platform 100 can be coupled to the base 21 via themounting frame member 8.

FIG. 9 illustrates another exploded view of the unmanned multi-rotoraircraft of FIG. 8 carrying a stabilizing platform with a payloaddevice, in accordance with an embodiment of the present invention.

FIG. 10 illustrates another view of the assembled unmanned multi-rotoraircraft of FIG. 8 carrying a stabilizing platform with a payloaddevice, in accordance with an embodiment of the present invention.

FIG. 11 illustrates another view of the assembled unmanned multi-rotoraircraft of FIG. 8 carrying a stabilizing platform with a payloaddevice, in accordance with an embodiment of the present invention.

FIG. 12 illustrates a view of an assembled two-axis stabilizing platformwith a payload device, in accordance with an embodiment of the presentinvention. Unlike FIGS. 1-6, instead of the second motor 5 directlydriving the second frame member 4, the fastener 13 is replaced with afourth motor 25 which directly drives the connecting assembly 12 torotate, thereby causing the second frame member 4 to rotate relative tothe third frame member 6. The connecting assembly 12 and the secondframe member 4 form a parallelogram structure and rotate at the sameangle, so that the rotation trajectory of the second frame member 4 isnot affected. Meanwhile, the connecting assembly 12 provides effectivesupport for the two open ends of the second frame member 4 along thevertical direction, increasing the load capacity and rigidity of thesecond frame member 4, reducing the deformation and weight thereof.

FIG. 13 illustrates a view of an assembled three-axis stabilizingplatform with a payload device, in accordance with an embodiment of thepresent invention. Unlike the two-axis stabilizing platform shown inFIG. 12, the frame assembly of the illustrated stabilizing platformfurther includes a mounting frame member 8, and the motor assemblyfurther includes the third motor 7 which directly drives the third framemember 6 to rotate relative to the mounting frame member 8. To achievecircumferential rotation of the payload device 1 in order to performpanoramic photography within a 360 degree range, the mounting framemember 8 is mounted to a helicopter or a multi-rotor aircraft. The thirdframe member 6 can rotate relative to the mounting frame member 8 aroundthe Z axis.

FIG. 14 illustrates a view of an assembled two-axis stabilizing platformwith a payload device, in accordance with an embodiment of the presentinvention. Unlike the stabilizing platform shown in FIG. 12, the motorassembly of the illustrated stabilizing platform further includes thesecond motor 5, which directly drive the second frame member 4 to rotaterelative to the third frame member 6. The second motor 5 can anauxiliary actuator and, in conjunction with the fourth motor 25, drivethe second frame member 4 to rotate. Since the connecting assembly 12and the second frame member 4 form a parallelogram structure, the secondmotor and the fourth motor can be used together to drive the rotation ofthe second frame member 4. It is appreciated that the second motor 5 andthe fourth motor 25 can also independently drive the rotation of thesecond frame member 4.

FIG. 15 illustrates a view of an assembled three-axis stabilizingplatform with a payload device, in accordance with an embodiment of thepresent invention. Unlike the stabilizing platform shown in FIG. 14, theframe assembly of the illustrated stabilizing platform further includesa mounting frame member 8, and the motor assembly further includes thethird motor 7 which directly drives the third frame member 6 to rotaterelative to the mounting frame member 8. To achieve circumferentialrotation of the payload device 1 in order to perform panoramicphotography within a 360 degree range, the mounting frame member 8 ismounted to a helicopter or a multi-rotor aircraft. The third framemember 6 can rotate relative to the mounting frame member 8 around the Zaxis.

FIG. 16 illustrates an exploded view of a two-axis stabilizing platformwith a payload device, in accordance with an embodiment of the presentinvention. When the axis K of the lens of the payload device 1 becomesperpendicular to the plane formed by the X axis and Y axis, the rotationof the second frame member 4 can only drive the lens of the payloaddevice 1 to scan within a given range around in the orthogonal plane andnot the rotation of the lens itself. In order to achieve full adjustmentof the angle of the lens of the payload device 1 even when the axis ofthe lens is rotated to be perpendicular to the plane formed by the Xaxis and Y axis, the motor assembly includes an additional motor fordirectly driving the payload device 1 to rotate around the K axis. Whenthe K axis is parallel or coaxial with the Y axis, the rotation of thesecond frame member 4 can be used to achieve the rotation of the lens ofthe payload device 1. When the K axis is perpendicular to the Y axis,the rotation of the lens of the payload device 1 can be achieved usingthe additional motor.

FIG. 17 illustrates an exploded view of a stabilizing platform with apayload device, in accordance with an embodiment of the presentinvention. When the axis K of the lens of the payload device 1 becomesperpendicular to the plane formed by the X axis and Y axis, the rotationof the second frame member 4 can only drive the lens of the payloaddevice 1 to scan within a given range around in the orthogonal plane andnot the rotation of the lens itself. In order to achieve full adjustmentof the angle of the lens of the payload device 1 even when the axis ofthe lens is rotated to be perpendicular to the plane formed by the Xaxis and Y axis, the motor assembly includes an additional motor fordirectly driving the payload device 1 to rotate around the K axis. Whenthe K axis is parallel or coaxial with the Y axis, the rotation of thesecond frame member 4 can be used to achieve the rotation of the lens ofthe payload device 1. When the K axis is perpendicular to the Y axis,the rotation of the lens of the payload device 1 can be achieved usingthe additional motor.

FIG. 18 illustrates a view of an assembled stabilizing platform with apayload device, in accordance with an embodiment of the presentinvention.

FIG. 19 illustrates another view of the assembled stabilizing platformwith a payload device shown in FIG. 18, in accordance with an embodimentof the present invention.

FIG. 20 illustrates an exploded view of a multi-rotor aircraft carryinga three-axis stabilizing platform with a payload device, in accordancewith an embodiment of the present invention. The multi-rotor aircraftmay include four, six, eight, or any suitable number of rotors. Thestabilizing platform can include a two-axis stabilizing platform such asdiscussed in connection with the exemplary embodiment 1, or a three-axisstabilizing platform such as discussed in connection with the exemplaryembodiment 2. As illustrated, the UAV can include a multi-rotor mount200, IMU module, GPS, and other components. The multi-rotor mount 200can include a base 21, multiple equispaced support arms 22 connected tothe base 21, and rotor members 23 disposed on the support arms 22. Thesupport arms 22 can be connected to the base 21 via plugging mechanism,welding, screws, riveting, and the like. The positioning bracket 9 canbe coupled to the mounting frame member 8, for example, via screws. Thestator of the third motor 7 can be disposed on the positioning bracket9. It is appreciated that, in various embodiments, the positions of thestator and rotor of the third motor 7 can be interchangeable.

FIG. 21 illustrates a view of a multi-rotor aircraft carrying athree-axis stabilizing platform with a payload device, in accordancewith an embodiment of the present invention.

FIG. 22 illustrates another view of a multi-rotor aircraft carrying athree-axis stabilizing platform with a payload device, in accordancewith an embodiment of the present invention.

FIG. 23 illustrates exemplary components of a stabilizing platform 2300,in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Methods and apparatus for a stabilizing a payload device are provided.In some embodiments, the payload devices may include imaging devices(including but not limited to video camera or camera) and non-imagingdevices (including but not limited to microphone, sample collector). Astabilizing platform, such as a camera mount, may be provided forsupporting and stabilizing the payload platform. The stabilizingplatform may comprise a frame assembly adapted to hold the payloaddevice, a controller assembly, and a motor assembly. The controllerassembly may include a measurement member configured to detect or obtainstate information associated with the payload device. The stateinformation may include velocity, orientation, attitude, gravitationalforces, acceleration, position, and/or any other physical stateexperienced by the payload device. For example, the state informationmay include an angular and/or linear velocity and/or acceleration, or anorientation or inclination of the payload device. In some embodiments,the measurement member may include an inertial measurement membercomprising one or more gyroscopes, velocity sensors, accelerometers,magnetometers, and the like. In other embodiments, other types ofstate-detecting sensors may be used instead of or in addition to theinertial measurement member.

The controller assembly may also include a controller for calculatingposture information associated with the payload device based on thestate information obtained by the measurement member. For example,detected angular velocity and/or linear acceleration of the payloaddevice may be used to calculate the attitude of the payload device withrespect a pitch, roll and/or yaw axis of the payload device.

Based on the calculated posture of the payload device, one or more motorsignals may be generated to control the motor assembly. The motorassembly may be configured to directly drive the frame assembly torotate around at least one or a pitch, roll or yaw axis of the payloaddevice so as to adjust the posture of the payload device (e.g.,. theshooting angle of an imaging device). The motor assembly can compriseone or more motors that are respectively coupled to one or morerotational axis (e.g., pitch, roll or yaw) of the payload device. Insome embodiments, one or more of the rotational axes (e.g., pitch, rolland yaw) intersect with the payload device.

In some embodiments, the rotation order of the payload device isselected to allow the payload device to be rotated without the problemof “gimbal lock” under ordinary operational circumstances for thepayload device, such as when pointing straight down. For example, in apreferred embodiment, the rotation order is pitch, roll and yaw from theinnermost to outermost rotational axis.

In the present invention, the motor assembly is configured to directlydrive the frame assembly, causing the payload device to rotate aroundrotational axis. Compared with the use of mechanical gear drivemechanisms, the use of direct-drive motors offers reduced energyconsumption while allowing step-less control of the motor speed.Furthermore, using direct-drive motors, the response time is reducedbetween the posture change of the carrier and the correspondingcompensating change to the stabilizing platform due to faster responsetime of the electric motors. Thus, the pointing direction of the payloaddevice may be quickly adjusted (e.g., to point at a moving target). Insome cases, a predetermined position or posture of the payload devicemay be maintained. Further, the payload device may be stabilized againstunwanted movement such as vibrations or shakes caused by the carrier orother external factors. In cases where the payload device is an imagingdevice, the quality of images acquired by the payload device can beimproved.

Exemplary Embodiment 1

FIG. 1 illustrates a structural schematic view of stabilizing platform,in accordance with an embodiment of the present invention. Thestabilizing platform may be configured to hold a payload device 1 suchas an imaging device or a non-imaging device (e.g., microphone, particledetector, sample collector). An imaging device may be configured toacquire and/or transmit one or more images of objects within the imagingdevice's field of view. Examples of an imaging device may include acamera, a video camera, cell phone with a camera, or any device havingthe ability to capture optical signals. A non-imaging device may includeany other devices such as for collecting or distributing sound,particles, liquid, or the like. Examples of non-imaging devices mayinclude a microphone, a loud speaker, a particle or radiation detector,a fire hose, and the like.

In some embodiments, the stabilizing platform may be adapted to bemounted or otherwise coupled to a movable object such as a motorized ornon-motorized vehicle or vessel, robot, human, animal, or the like. Forexample, the stabilizing platform may be mounted to the base of a mannedor unmanned aerial vehicle (UAV).

As illustrated by FIG. 1, a two-axis stabilizing platform is providedthat provides two axes of rotation for a payload device 1 mountedtherein. In particular, the payload device is allowed to rotate aroundthe pitch (X) axis, and a roll (Y) axis 16. The stabilizing platformcomprises a frame assembly, controller assembly and a motor assembly.The frame assembly includes a first frame member 2, a second framemember 4, and a third frame member 6. The first frame member 2 isadapted to be coupled to the payload device 1 such as an imaging device.In some embodiments, the payload device is affixed to the first framemember 2 such that the payload device and the first frame member aremovable as a whole. The first frame member 2 is rotatably coupled to thesecond frame member 4 along a rotational (pitch) axis X 14. The secondframe member 4 is rotatably coupled to the third frame member 6 on arotational (roll) axis Y 16. In various embodiments, the shape, size andother characteristics of the payload device are not limited to thoseshown in FIG. 1. For example, the shape of the payload device may berectangular, spherical, ellipsoidal, or the like.

In the illustrated embodiment, the motor assembly comprises a firstmotor 3 and a second motor 5. The first motor 3 is configured todirectly drive the first frame member 2 to rotate around the X (pitch)axis 14 relative to the second frame member 4. The second motor 5 may beconfigured to directly drive the second frame member 4 to rotate aroundthe Y (roll) axis 16. As discussed above, compared with mechanicaldriving means, direct-drive motors (e.g., compact motors or miniaturizedmotors) provide at least the following benefits: (1) direct-drive motorstypically require relatively less energy, thereby promoting energyefficiency and environmental protection; (2) the motors may becontrolled in a stepless fashion, reducing the response time, andenabling fast and timely adjustment in response to various posturechanges of the carrier. Thus, the stability of the payload device (e.g.,imaging device) is improved.

In some embodiments, additional support structure(s) may be optionallyprovided to further stabilize the platform. It is appreciated that suchsupport structures are optional and thus not required in all embodimentsof the present invention. As illustrated in FIG. 1, two free ends of thesecond frame member 4 extend outwardly while the first frame member 2and the payload device 1 as a whole are rotatably disposed between thetwo free ends. When the second motor 5 drives the second frame member 4into rotation, the longer the two free ends of the second frame member4, the farther the center of gravity of the first frame member 2 and thepayload device 1 may be located away from the pivot point of the secondframe member 4, causing instability (e.g., shaking) of the second framemember 4 and hence the payload device 1 during rotation of the secondframe member 4. In order to reduce or eliminate such instability of thesecond frame member 4, a connecting assembly 12, such as shown in FIG.1, may be included to provide additional support. The two free ends ofthe connecting assembly 12 may be rotatably coupled to the two open endsof the second frame member 4 respectively, and the connecting assembly12 may be coupled to the third frame member 6 via a fastener 13. In someembodiments, the free ends of the connecting assembly 12 are hingedlyconnected to the second frame member 4 to form a part of a parallelogramstructure. According to the principles of parallelogram, when the secondframe member 4 rotates at a certain angle relative to the third framemember 6, the connecting assembly 12 rotates a corresponding angletherewith without significantly affecting the rotation trajectory of thesecond frame member 4. In addition, the connecting assembly 12 iscoupled to the third frame member 6 via the fastener 13, therebyproviding effective support for the two open ends of the second framemember 4 along the vertical direction and increasing the load capacityand rigidity of the second frame member 4. Thus, any deformation of thesecond frame member 4, for example, caused by a heavy payload device,can be reduced. In addition, with the additional support provided by theconnecting assembly 12, the size and/or weight of the second framemember 4 may be reduced. Correspondingly, the size (e.g., diameter) ofthe second motor 5 that is used to directly drive the second framemember 4 may be reduced.

In some embodiments such as shown in FIG. 2, the connecting assembly 12comprises a first connecting member 121, a second connecting member 122and a third connecting member 123 that are sequentially and hingedlyconnected. A free end of the first connecting member 121 is hingedlyconnected with a first distal end of the second frame member 4, the freeend of the third connecting member 123 is hingedly connected with asecond distal end of the second frame member 4, and the secondconnecting member 122 is coupled to the third frame member 6 so that theconnecting assembly 12 and the second frame member 4 jointly form aportion of a parallelogram. In order to enhance the stability of theparallelogram, the second connecting member 122 is preferably coupled tothe third frame member 6 (e.g., via the fastener 13) at the midpoint ofthe second connecting member 122.

In some embodiments, a mounting arm 10 is provided, such as shown inFIG. 1, to connect the connecting member 12 with the third frame member6. As illustrated, one end of the mounting arm 10 is coupled to thethird frame member 6 and the other end of mounting arm 10 is providedwith a positioning hole 11 adapted to be coupled with the fastener 13.The second connecting member 122 is fastened to the mounting arm 10 viathe fastener 13.

In a preferred embodiment, the rotational (pitch) axis X 14 of the firstframe member 2 is orthogonally disposed relative to the rotational axisY 16 of the second frame member 4, for example, to allow the motors toeasily and timely adjust the rotation of the frame assembly. In otherembodiments, the rotational axes may not be orthogonally disposed toeach other.

In some embodiments, a stator of the first motor 3 is affixed to thefirst frame member 2 and a rotor of the first motor 3 is affixed to thesecond frame member 4. In such embodiments, the first motor 3 may beconfigured to directly drive the second frame member 4, thereby causingthe first frame member 2 to rotate relative to the second frame member4. Similarly, in some embodiments, the stator of the second motor 5 isaffixed to the third frame member 6 and the rotor of the second motor 5is affixed to the second frame member 4. In such embodiments, the secondmotor 5 may be configured to directly drive the second frame member 4,thereby causing the second frame member 4 to rotate relative to thethird frame member 6. It is appreciated that the positions of the statorand the rotor of the first motor 3 may be interchangeable. Likewise, thepositions of the stator and the rotor of the second motor 3 may beinterchangeable.

To further increase the stability for the payload device, the center ofgravity of the first frame member 2 and the payload device 1 as a wholeis preferably located on the rotational (pitch) axis X 14 of the firstframe member 2. In some embodiments, the pitch axis intersects with thepayload device 1. It is appreciated that when the center of gravity ofthe first frame member 2 and the payload device 1 is positioned on therotational axis X 14 of the first frame member 2, the rotation of thefirst frame member 2 does not generate any torque. In other words, thefirst frame member 2 is not likely to be any swing movement caused bythe torque. Thus, the stability of the payload device is enhanced duringrotation. In addition, in the preferred embodiment, when the carrier ismoving smoothly, that is, when little or no motor drive stabilization isrequired, the first frame member 2 and the payload device 1 is also in adynamically balanced state.

Similarly, to provide enhanced stability and avoid torque generated byrotation around the rotational Y (roll) axis 16, in a preferredembodiment and as shown in FIG. 1, the center of gravity of the firstframe member 2, the second frame member 4 and the payload device 1 as awhole is located on the rotational axis Y 16 of the second frame member6. In some embodiments, the rotational Y (roll) axis 16 intersects withthe payload device 1.

In some embodiments, the frame assembly may comprise one or moreadjustment members for adjusting the dimensions or rotational axes ofthe frame assembly. Such adjustment members may allow the frame assemblyto accommodate payload devices of different dimensions, shapes and/orweight. In addition, the adjustment may be necessary, for example, toalign the center of gravity with a rotational axis as discussed above,such as to position the center of gravity of the payload device and thefirst frame member 2 as a whole on the pitch (X) axis 14, and/or toposition the center of gravity of the payload device, the first framemember 2 and the second frame member 4 as a whole on the roll axis 16.For example, as illustrated in FIG. 1, the first frame member 2 caninclude one or more adjustment members 19 (e.g., slits, holes) foradjusting the position of the payload device 1 and/or the first motor 3relative to the first frame member 2. Such adjustment may be required,for example, to align the center of gravity of the payload device 1 andthe first frame member 2 as a whole on the rotational axis 14 of thefirst motor 3. As another example, the second frame member 4 can includeone or more adjustment members 30 of FIG. 1 for adjusting the positionof the first frame member 2 relative to the second frame member 4. Forexample, the first frame member 2 can be positioned further from orcloser to the pivot point of the second frame member 4 depending on thesize or shape of the payload device 1. As another example, the secondframe member 4 can include one or more adjustment members 32 foradjusting the position of the second motor 5 relative to the secondframe member 4. Such adjustment may be required, for example, to alignthe center of gravity of the payload device 1, the first frame member 2,and the second frame member 4 as a whole on the rotational axis 16 ofthe second motor 5. The third frame member 6 can also include one ormore adjust members 33 for changing the position of the second framemember 4 relative to the third frame member 6. The third frame member 6may also include one or more adjustment members 34 for changing thedimensions of the third frame member 4 so as to accommodate payloaddevices of various sizes.

In a preferred embodiment, at least one of the first motor 3 or thesecond motor 5 is implemented using a brushless DC electric motor. Thebrushless DC motors have the following benefits: (1) reliableperformance, reduced wear and/or malfunction rate, and a longer servicelife (about six times) than that of a brushed motor due to commutationwith electronics instead of mechanical commutators (2) low no-loadcurrent because brushless DC motors are static motors; (3) highefficiency; and (4) small size. In various embodiments, other types ofmotors may be used instead of or in addition to brushless DC motors.

In some embodiments, the controller assembly comprises a controller anda measurement member. The measurement member may be configured tomeasure or obtain state information associated with the payload device,and/or with objects other than the payload device, such as the frameassembly, the motors, the carrier, and the like. The measurement membermay include an inertial measurement unit, a compass, a GPS transceiver,or other types of measurement components or sensors. For example, themeasurement member may include one or more gyroscopes for detectingangular velocity and one or more accelerometer for detecting linearand/or angular acceleration of an object (e.g., payload device, frameassembly, and/or carrier). The state information may include angularand/or linear velocity and/or acceleration of the object, positionalinformation, and the like. Such state information may be relative orabsolute. In some embodiments, the measurement member may be configuredto measure state information with respect to more than one rotationalaxis of the object. In some embodiments, the measurement member mayobtain information that relate to at least two of the rotational axes.For example, the measurement member may obtain information related toboth the pitch and roll axes of the object. Or, the state informationmay pertain to all of the pitch, roll and yaw axes of the object. Invarious embodiments, the measurement member may be coupled to thepayload device 1, the frame assembly, the motor assembly, the carrier,or the like.

In some embodiments, the controller may be configured to calculateposture information of the object based on the state informationdetected by the measurement member and to provide one or more motorsignals based on the posture information. Such posture information mayinclude the pitch, roll, yaw axes of the object, orientation orinclination of the object with respect to the axes, velocity and/oracceleration, and the like. In some cases, the posture information maybe calculated based on angular velocity information (e.g., as providedby the measurement member or from other sources). In other cases, theposture information may be calculated based on both angular velocityinformation and linear acceleration information. For example, the linearacceleration information may be used to modify and/or correct theangular velocity information.

Based on the posture information, one or more motor signals may begenerated to cause forward rotation, reverse rotation of the motors(e.g., first motor 3 and second motor 5), and to adjust the speed of therotations. In response to the one or more motor signals, the motors(e.g., first motor 3 and second motor 5) can directly drive theirrespective portions of the frame assembly to rotate in response to theone or more motor signals. As a result, the payload device is allowed torotate around at least one of the pitch or roll axes. Such rotation maybe necessary for stabilizing the payload device and/or for maintaining apredetermined position or posture.

Exemplary Embodiment 2

FIGS. 2-6 illustrate example views of a stabilizing platform, inaccordance with a second embodiment of the present invention. Theplatform illustrated in this embodiment is similar to that illustratedin the first embodiment as discussed in connection with FIG. 1. In someembodiments, the stabilizing platform may be adapted to be mounted orotherwise coupled to a movable object such as a motorized ornon-motorized vehicle or vessel, robot, human, animal, or the like. Forexample, the stabilizing platform may be mounted to the base of a mannedor unmanned aerial vehicle (UAV).

However, as illustrated by FIGS. 2-6, the stabilizing platform in thesecond embodiment provides three axes of rotation for a payload devicemounted therein, instead of the two axes of rotation provided by thestabilizing platform in the first embodiment. More specifically, asshown in FIG. 2, the payload device is allowed to rotate around thepitch (X) axis 14, roll (Y) axis 16, and yaw (Z) axis 18. The three-axisstabilizing platform comprises a frame assembly adapted to support apayload device 1 (e.g., imaging device such as a camera), a motorassembly, a controller assembly.

As illustrated by FIG. 2, the frame assembly comprises a first framemember 2, a second frame member 4, a third frame member 6 and a fourthframe member 8. The first, second and third frame members may be similarto those described in connection with FIG. 1. In particular, the firstframe member 2 is adapted to be coupled to the payload device 1 such asan imaging device. In some embodiments, the payload device is affixed tothe first frame member 2 such that the payload device and the firstframe member are movable as a whole. The second frame member 4 isrotatably coupled to the first frame member 2 around a rotational(pitch) axis X 14, so that the first frame member 2 and hence thepayload device 1 may tilt upward or downward. The second frame member 4is rotatably coupled to the third frame member 6 on a rotational (roll)axis Y 16, so that the second frame member 4 can rotate around the rollaxis 16 relative to the third frame member 6, causing the first frameand the payload device as a whole to rotate around the roll axis 16.Thus, when the carrier rolls to the left or to the right, the payloaddevice can be made to roll to the right or to the left in order tomaintain stability (e.g., a predetermined posture). The third framemember 6 is rotatably coupled to the fourth frame member 8 on arotational Z (yaw) axis 18, allowing the payload device 1 tocircumferentially rotate (e.g., up to 360 degrees), for example, inorder to perform panoramic photography. In some embodiments, the fourthframe member 8 may be used to mount the stabilizing platform to or tofacilitate the carrying of the stabilizing platform by a carrier such asa aerial vehicle, motor vehicle, ship, robot, human, or any othermovable object. As another example, the stabilizing platform may behandheld by a human, for example, to perform dynamic videography orphotography.

In the illustrated embodiment, the motor assembly comprises a firstmotor 3, a second motor 5 and a third motor 7. The first motor 3 isconfigured to directly drive the first frame member 2 to rotate aroundthe X (pitch) axis 14 relative to the second frame member 4. The secondmotor 5 may be configured to directly drive the second frame member 4 torotate around the Y (roll) axis 16. The third motor 7 may be configuredto directly drive the third frame member 6 to rotate around the yaw (Z)axis 18. The advantages of using direct-drive motors are discussed abovein connection with FIG. 1.

Also as discussed in connection with FIG. 1, additional structure(s) maybe optionally included to provide additional support or stabilization.For example, a connecting assembly 12 similar to that described in FIG.1 or a similar structure may be provided to reinforce or stabilize thesecond frame member 4, for example, when it rotates relative to thethird frame member 6.

Advantageously, the rotation order of pitch, roll and yaw (from theinnermost to outermost rotational axis) is selected to allow the payloaddevice to be rotated without the problem of “gimbal lock” under ordinaryoperational circumstances for the payload device, such as when pointingstraight down.

In a preferred embodiment, the rotational (pitch) axis X 14 of the firstframe member 2, rotational (roll) axis Y 16 of the second frame member4, and the rotational (yaw) axis Z 18 of the third frame member 8 areorthogonally disposed to each other. Such an arrangement may allow themotors to easily and timely adjust the rotation angles of the frameassembly. In other embodiments, the rotational axes may not beorthogonally disposed to each other.

As discussed in connection with FIG. 1, in some embodiments, a stator ofthe first motor 3 is affixed to the first frame member 2 and a rotor ofthe first motor 3 is affixed to the second frame member 4. In suchembodiments, the first motor 3 may be configured to directly drive thesecond frame member 4, thereby causing the first frame member 2 torotate relative to the second frame member 4. Similarly, in someembodiments, the stator of the second motor 5 is affixed to the thirdframe member 6 and the rotor of the second motor 5 is affixed to thesecond frame member 4. In such embodiments, the second motor 5 may beconfigured to directly drive the second frame member 4 to rotaterelative to the third frame member 6. Similarly, in some embodiments,the stator of the third motor 7 is affixed to the fourth frame member 8and the rotor of the third motor 7 is affixed to the third frame member6. In such embodiments, the third motor 7 may be configured to directlydrive the third frame member 6 rotate relative to the fourth framemember 8. The third motor 7 may be coupled to the fourth frame member 8via a bracket 9. It is appreciated that the positions of the stator andthe rotor may be interchangeable for the first motor 3, the second motor5 and the third motor 7.

As discussed in connection with FIG. 1, to increase the stability of theplatform, the center of gravity of the first frame member 2 and thepayload device 1 as a whole is preferably located on the rotational(pitch) axis X 14 of the first frame member 2. In some embodiments, thepitch axis intersects with the payload device 1. Similarly, the centerof gravity of the first frame member 2, the second frame member 4, andthe payload device 1 as a whole is preferably located on the rotational(roll) axis Y 16 of the second frame member 4. In some embodiments, therotational (roll) axis Y 16 intersects with the payload device 1.Likewise, the center of gravity of the first frame member 2, the secondframe member 4, the third frame member 6, and the payload device 1 as awhole is preferably located on the rotational (yaw) axis Z 18 of thethird frame member 6. In some embodiments, the rotational (yaw) axis Z18 intersects with the payload device 1.

As discussed in connection with FIG. 1, in some embodiments, the frameassembly may comprise one or more adjustment members for adjusting thedimensions or rotational axes of the frame assembly. Such adjustment mayallow the frame assembly to accommodate payload devices of differentdimensions, shapes or weights. In addition, the adjustment may benecessary, for example, to align a center of gravity and a rotationalaxis such as discussed above. For example, as illustrated in FIG. 2, thefirst frame member 2 can include one or more adjustment members 19(e.g., slits, holes) for adjusting the position of the payload device 1and/or the first motor 3 relative to the first frame member 2. Suchadjustment may be required, for example, to align the center of gravityof the payload device 1 and the first frame member 2 as a whole on therotational axis 14 of the first motor 3. As another example, the secondframe member 4 can include one or more adjustment members 30 foradjusting the position of the first frame member 2 relative to thesecond frame member 4. For example, the first frame member 2 can bepositioned further from or closer to the pivot point of the second framemember 4 depending on the size or shape of the payload device 1. Asanother example, the second frame member 4 can include one or moreadjustment members 32 for adjusting the position of the second motor 5relative to the second frame member 4. Such adjustment may be required,for example, to align the center of gravity of the payload device 1, thefirst frame member 2, and the second frame member 4 as a whole on therotational axis 16 of the second motor 5. The third frame member 6 canalso include one or more adjust members 33 for changing the position ofthe second frame member 4 relative to the third frame member 6. Thethird frame member 6 may also include one or more adjustment members 34for changing the dimensions of the third frame member 4 so as toaccommodate payload devices of various sizes. Furthermore, the thirdframe member 6 may include one or more adjustment members 35 foradjusting the position of the third motor 7 and/or the fourth framemember 8 relative to the third frame member 6. Likewise, the fourthframe member 8 may include one or more adjustment members 36 foradjusting the position of the third frame member 6 and/or the thirdmotor 7 relative to the fourth frame member 8.

In preferred embodiments, at least one of the first motor 3, the secondmotor 5 or the third motor 7 is implemented using a brushless DCelectric motor. As discussed above in connection with FIG. 1, brushlessDC motors are preferred because they provide or enable reliableperformance, reduced wear and malfunction rate, a longer service life,low no-load current, high efficiency, and reduced size. In variousembodiments, other types of motors may be used instead of or in additionto brushless DC motors.

In some embodiments, the controller assembly may be similar to thatdescribed in connection with FIG. 1. In particular, the controllerassembly may comprise a controller and a measurement member. Themeasurement member may be configured to measure state informationassociated with an object (e.g., payload device, frame assembly, and/orcarrier). The state information may be related to more than onerotational axis of the object (e.g., pitch, roll and yaw). In someembodiments, the controller may be configured to calculate postureinformation of the object based on the state information detected by themeasurement member and to provide one or more motor signals based on theposture information. Such posture information may include the pitch,roll, yaw axes of the object, orientation or inclination of the objectwith respect to the axes, velocity and/or acceleration, and the like.The posture information may be calculated based on angular and/or linearvelocity and/or acceleration information (e.g., as provided by themeasurement member or from other sources).

Based on the posture information, one or more motor signals may begenerated to cause forward rotation, reverse rotation of the motors(e.g., first motor 3, second motor 5, and third motor 7), and to adjustthe speed of the rotations. In response to the one or more motorsignals, the motors (e.g., first motor 3, second motor 5, and thirdmotor 7) can directly drive their respective portions of the frameassembly to rotate in response to the one or more motor signals. As aresult, the payload device is allowed to rotate around at least one ofthe pitch, roll or yaw axes, for example, to maintain a stabilizedposition or posture.

Exemplary Embodiment 3

FIGS. 12-15 illustrate examples of a third embodiment of the presentinvention. The third embodiment may be similar to the first embodimentand the second embodiment, except that the fastener 13 is replaced witha fourth motor 25 which directly drives the connecting assembly 12 torotate relative to the third frame member 6. Thus, the connectingassembly 12 brings the second frame member 4 to rotate therewith. Hence,the fourth motor may be auxiliary to the second motor 5. It may beappreciated that, in some embodiments, the fourth motor may replace thesecond motor 5 and serve as a motive power source by which the secondframe member 4 rotates relative to the third frame member 6. In suchembodiments, the second motor 5 may be optional and the motor assemblymay only include the first motor 3, the third motor 7 and the fourthmotor.

In various embodiments, the stabilizing platform discussed herein may bemounted or otherwise coupled to a movable object such as those describedherein. FIG. 7 illustrates a structural schematic view of an unmannedaerial vehicle (UAV) 702 carrying a stabilizing platform 704 with apayload device 706, in accordance with an embodiment of the presentinvention. The stabilizing platform 704 may be similar to the two-axisstabilizing platform discussed in connection with FIG. 1 or thethree-axis stabilizing platform discussed in connection with FIG. 2-6.The payload device 706 may include an imaging device (camera) ornon-imaging device such as discussed above. The stabilizing platform ismounted to the base of the UAV.

During operation, the UAV may be remotely controlled to approach atarget object the images of which are to be acquired. Subsequently, thestabilizing platform may be controlled, for example, by the controllerassembly and/or a remote control, to stabilize the payload device so asto improve the quality of images captured by the device. For example,the measurement member of the stabilizing platform may calculate postureinformation of the payload device and/or the UAV and provide motorsignals to the motor assembly for directly drive the rotation of theframe assembly to 1) stabilize the payload device with respect to thetarget object; and/or 2) maintain the payload device at a predeterminedposture with respect to the target object.

While preferred embodiments of the present invention have been shown anddescribed herein, it will be obvious to those skilled in the art thatsuch embodiments are provided by way of example only. Numerousvariations, changes, and substitutions will now occur to those skilledin the art without departing from the invention. It should be understoodthat various alternatives to the embodiments of the invention describedherein may be employed in practicing the invention. It is intended thatthe following claims define the scope of the invention and that methodsand structures within the scope of these claims and their equivalents becovered thereby.

What is claimed is:
 1. An unmanned aerial vehicle (UAV) comprising: (a)a central body; (b) a plurality of propulsion units supported away fromthe central body and configured to rotate to generate lift during flightof the UAV; (c) a frame assembly adapted to hold a device during theflight of the UAV, wherein the frame assembly comprises: a first framemember configured to be coupled to the device; a second frame memberrotatably coupled to the first frame member on a pitch axis of thedevice; and a third frame member rotatably coupled to the second framemember on a roll axis of the device, wherein the third frame member ismovable about a yaw axis of the device relative to the central body; and(d) a motor assembly configured to directly drive the frame assembly inresponse to one or more motor signals so as to allow the device torotate around at least one of the pitch, roll or yaw axes.
 2. The UAV ofclaim 1, wherein the frame assembly is located beneath the central bodyduring flight of the UAV.
 3. The UAV of claim 1, wherein the frameassembly is located beneath the plurality of propulsion units duringflight of the UAV.
 4. The UAV of claim 1, wherein the motor assemblycomprises: a first motor configured to directly drive the first framemember to rotate around the pitch axis in response to at least one ofthe one or more motor signals; a second motor configured to directlydrive the second frame member to rotate around the roll axis in responseto at least one of the one or more motor signals; and a third motorconfigured to directly drive the third frame member to rotate around theyaw axis in response to at least one of the one or more motor signals.5. The UAV of claim 4, wherein a stator of the first motor is affixed tothe first frame member and a rotor of the first motor is affixed to thesecond frame member, or the rotor of the first motor is affixed to thefirst frame member and the stator of the first motor is affixed to thesecond frame member; and a stator of the second motor is affixed to thesecond frame member and a rotor of the second motor is affixed to thethird frame member, or the rotor of the second motor is affixed to thesecond frame member and the stator of the second motor is affixed to thethird frame member.
 6. The UAV of claim 4, wherein the motor assembly iscontrolled in a stepless manner.
 7. The UAV of claim 1, furthercomprising: (e) a controller assembly comprising: a measurement memberconfigured to obtain state information of the device; and a controllerconfigured to provide the one or more motor signals based at least inpart on posture information calculated from the state information. 8.The UAV of claim 7, wherein the measurement member is an inertialmeasurement unit and the state information obtained by the inertialmeasurement member comprises at least angular velocity and linearacceleration of the device.
 9. The UAV of claim 7, wherein thecontroller is configured to calculate posture information of the device.10. The UAV of claim 9, wherein the controller is configured tocalculate posture information of the UAV.
 11. The UAV of claim 7,wherein the measurement member is attached to the frame assembly. 12.The UAV of claim 7, wherein the measurement member is attached to thedevice.
 13. The UAV of claim 1, wherein the frame assembly furthercomprises an adjustment member for adjusting at least one of the pitch,roll, or yaw axis relative to the frame assembly.
 14. The UAV of claim1, wherein the device is configured to capture images.
 15. The UAV ofclaim 1, wherein the center of gravity of (i) the device and (ii) thefirst frame member, is located on the pitch axis.
 16. The UAV of claim1, wherein the center of gravity of (i) the device, (ii) the first framemember, and (iii) the second frame member, is located on the roll axis.17. The UAV of claim 1, wherein the center of gravity of (i) the device,(ii) the first frame member, (iii) the second frame member, and (iv) thethird frame member, is located on the yaw axis.
 18. The UAV of claim 1,wherein the third frame assembly is configured to rotate to up to 360degrees relative to the central body.
 19. A method for stabilizing adevice on a UAV, said method comprising: operating the UAV of claim 7 tocontrol flight of the UAV; calculating the posture information based atleast in part on the state information; providing, by the controllerassembly, one or more motor signals to the motor assembly based at leastin part on the calculated posture information; and in response to theone or more motor signals, driving, by the motor assembly, the frameassembly to rotate around at least one of the pitch, roll, or yaw axis.20. A method of collecting data about an object using a UAV, comprising:remotely operating the UAV of claim 1 to approach the object; andcontrolling the motor assembly to stabilize a device held by the frameassembly of the UAV.